1. Field of the Invention
The present invention relates to portable electronic devices such as laptop computers, word processors, etc.
2. Description of the Related Art
Portable computers, called laptop computers, have recently been gaining popularity for general use. The computers of this type comprises a housing and a display unit pivotably mounted thereon. The display unit is put on the housing when not in use, and is pivoted to an operating position when it is to be operated.
Conventionally, a portable computer has a software-based function to prevent wrong operation. Although this preventive function provides a certain measure of effectiveness, it may possibly be nullified when the computer itself is ready for operation.
Since a large number of heat-generating components are arranged in the computer housing, the computer is generally provided with a cooling mechanism. This cooling mechanism includes, for example, a cooling fan arranged in the housing. After the components are cooled by means of outside air which is introduced into the housing through intake ports in the housing by means of the fan, the air is discharged through exhaust ports formed in the housing.
In consideration of its portability, however, the portable computer is made as light in weight and compact as possible. It is difficult, therefore, to secure wide enough opening areas for the intake and exhaust ports in the housing therefore, so that sufficient cooling air cannot be easily introduced into the housing. Further, the cooling fan produces relatively loud operating sounds, which result in undesired noises.
Since the housing of the portable computer is compact, as described above, a large number of components must be efficiently arranged in the housing.
The portable computer is provided with a substantially rectangular keyboard unit, which is mounted on the housing so that its peripheral edge portion is supported thereby. If keys of the keyboard unit, especially the ones situated in the central portion of the keyboard unit, are deeply depressed, therefore, the central portion of the keyboard unit sometimes may bend in the direction of the depression. In such a case, the keyboard unit interferes with underlying electronic parts, thereby possibly damaging them.
Some conventional portable computers are provided with an expansion unit which can contain an expansion component for expanding the function of the computer. This expansion unit is removably mounted on the housing. In attaching the expansion unit to the housing, a unit-side connector is connected to a housing-side connector. In order to connect these two connectors with accuracy, they must be accurately positioned with respect to each other. Accordingly, the expansion unit and the housing should be manufactured with high accuracy, thus entailing increased costs.